Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis

Table 2 Measurements of vitamin B6 status before and after 30 day treatment

	Placebo group (n = 14)		B6 group (n = 14)		p value (baseline)^a	p value (treat)^b
	Before	After	Before	After
Plasma PLP (nmol/l)^c	22.8 (15.4–31.5)	23.6 (15.2–43.0)	27.0 (20.4–30.9)	144.5 (84.5–236.7)	<0.0001	<0.0001
Erythrocyte PLP (nmol/l)	26.0 (20.8–39.4)	41.6 (28.5–53.7)	44.6 (37.5–54.0)	116.4 (65.3–424.7)	0.623	0.002
αEAST	1.88 (1.67–1.99)	1.85 (1.64–1.96)	1.80 (1.68–1.93)	1.33 (1.29–1.40)	0.001	<0.0001
ΔtHcy (μmol/l)^c	19.2 (15.0–27.5)	17.9 (13.0–25.8)	24.9 (16.4–35.9)	19.0 (15.5–28.7)	<0.0001	0.086
Post-load XA (μmol/24 h)^c	173 (132–243)	137 (103–354)	183 (30–653)	102 (39–371)	0.001	0.042
4-PA (μg/24 h)	0.7 (0.5–1.2)	0.8 (0.5–170)	0.8 (0.5–2.0)	4.2 (0.8–12.8)	0.338	<0.0001

Data are presented as median (95% CI). ^aEffects of each baseline (before treatment) value on its post-treatment outcome. ^bTreatment effects of placebo and vitamin B6 were examined by analysis of covariance after adjusting for baseline value. ^cPlasma pyridoxal 5'-phosphate (PLP), urinary xanthurenic acid excretion in response to a tryptophan load test (post-load XA), and plasma total homocysteine (tHcy) concentrations were log-transformed to reach normal distribution for statistical analyses. αEAST, erythrocyte aspartate aminotransferase activity coefficient; 4-PA, 24 h 4-pyridoxic acid excretion; ΔtHcy, net homocysteine increase in response to a methionine load test.

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